A turbine engine, specifically a twin-spool turbine engine, conventionally includes, in the downstream direction, a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine and a low-pressure turbine.
Conventionally, in the present application, “upstream” and “downstream” are defined relative to the direction of the air flow in the turbine engine. Conventionally, in the present application, “internal” and “external”, “lower” and “higher” and “internal” and “external” are similarly defined radially relative to the axis of the turbine engine.
The low-pressure turbine of a turbine engine comprises a turbine shaft whereon several successive stages, each including an impeller and a guide vane are mounted. Each impeller comprises a disk, on the external periphery of which substantially radial blades are mounted, with the disks of the various impellers being coaxially connected together and to the driving shaft of the turbine rotor, using appropriate means. Each guide vane comprises an internal annular platform and an external annular platform between which substantially radial blades extend. The external platform of the guide vane comprises means for hooking and attaching on an external casing of the turbine. All the guide vanes form the stationary part of the engine called the stator.
The blades of each rotor wheel conventionally include lips at the radially external periphery thereof, and cooperate with a ring made of an abradable material so as to form sealing means of the labyrinth seal type.
Such a structure is known for instance from document FR 2 879 649.
In order to ensure high performances of the turbine engine, the clearances at the seals have to be checked and the leakage rate at the interface between the blade lips and the ring made of abradable material have to be limited.
Therefore the need exists for improving the efficiency of such labyrinth seals, while facilitating the mounting and the structure of the assembly.
The invention more particularly aims at providing a simple, efficient and cost-effective solution to this problem.